The Solar Still Cover Cooling With Different Technologies: A Review

ABSTRACT Low efficiency is the primary disadvantage of using solar stills (SSs). The efficiency is based on the SS's daily yield, which is strongly influenced by the cover temperature. Lowering the SS cover temperature increases the temperature difference between the SS cover and the basin water, and enhances the condensation process of the water vapor. Numerous technologies were employed and examined to improve the SS's performance through cover cooling. Water and air cooling are the most well‐known technologies for SS cover cooling. Also, thermoelectric technology is used to cool the cover plate via the Peltier effect. Other methods for SS cover cooling are being investigated, including integrated fins, nanoparticles, and an external heat exchanger. This review's objective is to examine the impact of cooling the SS cover on freshwater productivity. The results of the discussion showed that the water‐cooling technique increased freshwater productivity and energy efficiency by 107.7% and 103.4%, respectively, while reducing the cost of generated water by 38.4%. Utilization of air cooling with a velocity of 4 m/s raised the water productivity to 104%, while forced air (FA) cooling at a velocity of 5 m/s can provide a temperature difference of 21°C between the cover and basin water. When the external condenser was combined with the SS, the energy efficiency and freshwater productivity rose by 18.2% and 33.12%, respectively. Although the initial cost and energy consumption were higher, thermoelectric cooling increased water output by 74% and reported a cost of 0.0326 $/L. According to computational research, using nanofluid cooling increased water productivity by 11.09%. Also, the phase‐change material and nano‐phase‐change material augmented the freshwater productivity by 27.7% and 60.37%, respectively. This review is useful for researchers to expand their knowledge and help them select the best technique for enhancing SS cover cooling, taking economic and environmental feasibility into account.